import java.util.*;

public class Day01 {
    public static void main1(String[] args) {
        Scanner in = new Scanner(System.in);
        int left = in.nextInt(), right = in.nextInt();
        int sum = 0;
        for (int i = left; i <= right; i++) {
            sum += count(i, 2);
        }
        System.out.println(sum);
    }

    private static int count(int num, int key) {
        int ret = 0;
        while (num != 0) {
            ret += num % 10 == key ? 1 : 0;
            num /= 10;
        }
        return ret;
    }

    public static void main2(String[] args) {
        ArrayList<Integer> list1 = new ArrayList<>();
        list1.add(2);
        list1.add(2);

        ArrayList<Integer> list2 = new ArrayList<>();
        list2.add(1);
        list2.add(2);
        intersection(list1, list2);
    }

    public static ArrayList<Integer> intersection (ArrayList<Integer> nums1, ArrayList<Integer> nums2) {
        Set<Integer> set1 = new HashSet<>(nums1);
        Set<Integer> set2 = new HashSet<>(nums2);
        ArrayList<Integer> list = new ArrayList<>();
        for (Integer num : set1) {
            if (!set2.add(num)) {
                list.add(num);
            }
        }
        return list;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        StringBuilder line = new StringBuilder("bbcc");

        for (int i = 0; i < line.length() - 1; i++) {
            if (line.charAt(i) == line.charAt(i + 1)) {
                line.replace(i, i + 2, "");
                i -= 2;
                if (i < 0) i = -1;
            }
        }
        System.out.println(line.length() == 0 ? "0" : line);
    }
}
